U.S. patent application number 10/654599 was filed with the patent office on 2005-03-03 for apparatus and method for actuating or maintaining a seal by differential pressure.
Invention is credited to Lai, Jon W., Lim, Brian Y., Tombler, Thomas W. JR..
Application Number | 20050046180 10/654599 |
Document ID | / |
Family ID | 34218112 |
Filed Date | 2005-03-03 |
United States Patent
Application |
20050046180 |
Kind Code |
A1 |
Tombler, Thomas W. JR. ; et
al. |
March 3, 2005 |
Apparatus and method for actuating or maintaining a seal by
differential pressure
Abstract
In some embodiments of the invention, there is a method or
apparatus for tight sealing between a first space and a second
space. The second space is at least partially enclosed by a member.
The method or apparatus includes or performs the step of creating
or maintaining a pressure difference between a pressure in a third
space at a seal assembly and pressure in each of the first space
and the second space; and pushing, caused by the pressure
difference, against a seal in the seal assembly to tighten sealing
provided by the seal.
Inventors: |
Tombler, Thomas W. JR.;
(Santa Barbara, CA) ; Lim, Brian Y.; (Santa
Barbara, CA) ; Lai, Jon W.; (Santa Barbara,
CA) |
Correspondence
Address: |
Chiahua George Yu
Law Offices of C. George Yu
Ste.210
1250 Oakmead Pky.
Sunnyvale
CA
94085
US
|
Family ID: |
34218112 |
Appl. No.: |
10/654599 |
Filed: |
September 2, 2003 |
Current U.S.
Class: |
285/95 ; 285/106;
285/96; 285/97 |
Current CPC
Class: |
Y10T 29/49826 20150115;
F16L 2201/30 20130101; F16J 15/164 20130101; F16L 17/10
20130101 |
Class at
Publication: |
285/095 ;
285/096; 285/097; 285/106 |
International
Class: |
F16L 033/16 |
Claims
What is claimed is:
1. An apparatus for combining with at least a seal to seal a
member, wherein, when the member is to be sealed, the member is at
least partially in a first space and at least partially encloses at
least a portion of a second space, the member including an opening
to the second space, the apparatus comprising: a housing configured
to define, at least partially, a third space, and configured to
facilitate maintaining pressure level in the third space other than
merely by exposing the third space to the first space or to the
second space, wherein a pressure difference between the third space
and at least one of the first space or the second space creates a
force on the seal that promotes tightness of sealing provided by
the seal.
2. An apparatus as described in claim 1, configured wherein
pressure in the third space is capable of being maintained that
differs from both pressure in the first space and pressure in the
second space.
3. An apparatus as described in claim 1, wherein the housing
surrounds a segment of the member, and the third space is defined,
at least in part, by an external wall of the member and an internal
wall of the housing.
4. An apparatus as described in claim 1, wherein the member is
hereinafter referred to as first member, and the apparatus is to
facilitate resisting leakage between the first space and the second
space at a coupling between the first member and a second
member.
5. An apparatus as described in claim 4, wherein the first member
is made of a first material, and the second member is made of a
second material different from the first material.
6. An apparatus as described in claim 4, wherein the second member
comprises metal, the housing comprises metal, and the housing is to
be coupled to the second member via a metal-to-metal
connection.
7. An apparatus as described in claim 6, wherein the first member
comprises quartz, glass, ceramic, or plastic.
8. An apparatus as described in claim 4, wherein the second member
defines an interior space that is to be exposed to the second
space.
9. An apparatus as described in claim 8, wherein the first and
second members are conduits for flowing gas or fluid.
10. An apparatus as described in claim 4, wherein the second member
comprises at least one of a stopper, plug, end piece, or blank.
11. An apparatus as described in claim 1, further comprising an
indicator that is indicative of status of sealing being promoted by
the apparatus.
12. An apparatus as described in claim 11, wherein the indicator
reveals a condition that the apparatus is in an engaged state
wherein tightness of sealing is being promoted by the
apparatus.
13. An apparatus as described in claim 11, wherein the indicator
reveals a condition that tightness of sealing is not being
promoted, to meet a predetermined standard, by the apparatus.
14. An apparatus as described in claim 11, wherein the indicator
comprises a visual indicator.
15. An apparatus as described in claim 11, wherein the indicator
comprises an audio indicator.
16. An apparatus as described in claim 1, wherein the housing is
configured enable at least temporary coupling of the third space to
a pump or reservoir to establish a level of pressure in the third
space.
17. An apparatus as described in claim 16, wherein the housing
comprises a valve that can be closed to resist change in pressure
level in the third space even after the pump or reservoir is no
longer coupled to the third space.
18. An apparatus as described in claim 1, wherein the housing is
configured to enable electively ceasing to promote tightness of
sealing provided by the seal.
19. An apparatus as described in claim 18, wherein the housing
comprises a valve capable of opening the third space to at least
one of the first space or the second space to help reduce or
eliminate the pressure difference.
20. An apparatus as described in claim 18, wherein the housing is
configured to enable at least temporary coupling of the third space
to a pump or reservoir to actively reverse the pressure
difference.
21. An apparatus as described in claim 20, wherein the force that
promotes tightness of sealing was due to evacuation from the third
space to obtain a pressure level in the third space lower than that
in the at least one of the first or second space, and the pressure
difference is capable of being actively reversed by forcing gas or
fluid into the third space to obtain a new pressure level in the
third space higher than that in the at least one of the first or
second space.
22. An apparatus as described in claim 21, wherein the apparatus is
for use in an environment wherein chemicals are present, and the
forcing gas or fluid comprises forcing an inert gas or fluid that
does not react with the chemicals.
23. An apparatus as described in claim 20, wherein the new pressure
level is greater than atmospheric pressure.
24. An apparatus as described in claim 22, wherein the new pressure
level is less than about 200 pounds per square inch.
25. An apparatus as described in claim 18, further comprising a
mechanical element that switchably applies a mechanical force on
the seal to disrupt sealing provided by the seal.
26. An apparatus as described in claim 1, configured to be
compatible for use with equipment for at least one of chemical
vapor deposition, laser vaporization, chemical sensing, gas
sensing, spectrometry, chromatography, electronics, energy
conversion, piping, plumbing, gas lines, and fluid lines.
27. An apparatus as described in claim 1, wherein the member
comprises quartz, glass, ceramic, or plastic.
28. An apparatus as described in claim 1, wherein the force
tightens contact between the seal and the first member and between
the seal and the housing.
29. An apparatus as described in claim 1, wherein the seal
separates the first space from the third space.
30. An apparatus as described in claim 29, wherein the seal also
separates the second space from the third space.
31. An apparatus as described in claim 30, wherein the seal is a
single integrally-formed piece of material.
32. A seal assembly comprising an apparatus as described in claim 1
and the seal.
33. A seal assembly as described in claim 32, wherein: the seal is
hereinafter referred to as first seal; the pressure difference,
hereinafter referred to as first pressure difference, is a
difference between the third space and the first space; the seal
assembly further comprises a second seal; and the housing is also
configured wherein a second pressure difference, between the third
space and the second space, creates a force that promotes tightness
of sealing provided by the second seal.
34. A seal assembly as described in claim 33, wherein the first
seal is distinct from, and not integrally-formed with, the second
seal.
35. An apparatus as described in claim 32, wherein the seal
comprises an O-ring.
36. An apparatus as described in claim 1, configured to promote
tightness of sealing provided by the seal when pressure in the
third space is made lower than pressure in the first space and also
lower than pressure in the second space.
37. An apparatus as described in claim 1, configured to promote
tightness of sealing provided by the seal when pressure in the
third space is made lower than pressure in the first space.
38. An apparatus as described in claim 37, wherein the third space
is an evacuated space having less than atmospheric pressure when
the apparatus is in an activated state.
39. An apparatus as described in claim 1, wherein the third space
is bordered not by any concave wall defined by the member.
40. An apparatus as described in claim 1, wherein the seal
surrounds the member about an axis, and an axial cross section of
the seal defines a planar shape having a periphery having only
positive curvature.
41. An apparatus as described in claim 1, wherein pressure in the
third space is to be changed, for promoting sealing tightness, by
gas or fluid flow, the gas or fluid flow not primarily via any
concave channel defined by the member.
42. A method for tight sealing between a first space and a second
space, the second space being at least partially enclosed by a
member, the method comprising: creating a pressure difference
between a pressure in a third space at a seal assembly and pressure
in each of the first space and the second space; pushing, caused by
the pressure difference, against a seal in the seal assembly to
tighten sealing provided by the seal.
43. A reusable seal apparatus for connecting a first member with at
least a second member in a leak-proof manner, the seal apparatus
comprising: two seals each defining a channel through which the
first member is to be positioned, when being sealed; and a housing
defining a channel through which the first member is to be
positioned, when being sealed, wherein a volume is during sealing
contained between the two seals, the first member, and the seal
assembly housing, the volume to be evacuated to pressure lower than
ambient pressure, to cause a force on the seals to tighten
sealing.
44. A reusable seal apparatus as described in claim 43, wherein the
first member is of at least one of quartz or glass, and the seal
apparatus is to seal the first member to a second member that is of
metal, and the first member is a conduit that is to contain or
convey gas or liquid from a furnace.
45. A reusable seal apparatus as described in claim 43, further
comprising an indicator of status of the seal.
46. An apparatus for monitoring seal quality, the apparatus
comprising: a housing configured to contain, at least partially, a
space, pressure level within the space being indicative of
reliability or quality of sealing in a seal; a sensor responsive to
the pressure level or a change in the pressure level; and an
indicator configured to convey information indicative of
reliability or quality of sealing in the seal.
47. A method for monitoring seal quality, the method comprising:
maintaining a pressure level in a space, the pressure level being
indicative of the reliability or quality of sealing in a seal;
monitoring the pressure level; and providing an indicator based on
the monitoring of the pressure level.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to seals. Embodiments of the
present invention are especially suited for use in leak-resistant
(e.g., leak-proof) coupling of pieces made of different materials,
including, for example, coupling of quartz or glass tubing with
metal tubing, for example, in the production of materials or
electronic devices.
BACKGROUND
[0002] Seals are needed in a variety of fields. For example, seals
are needed in equipment for gas or liquid handling, electronics,
and materials. For example, chemical vapor deposition (CVD), laser
vaporization, and other methods for the fabrication of materials
and nanostructures often use a quartz tube and a heat source, where
the quartz tube needs to be connected to inlet or outlet gas lines
in a leak-proof manner. A well constructed, carefully arranged and
carefully operated conventional quartz-to-metal connection can
sometimes accomplish such leak-proof connection. However, such a
conventional quartz-to-metal connection can be relatively
expensive, require that the pieces being connected are made with
relatively high precision, and require care to set up and operate
if leaks are to be successfully avoided.
[0003] Various metal-to-metal connections are known and can be
leak-proof. Threaded metal connections, metal gaskets under
compression between tightened flanges, and metal welds give quality
seals. In U.S. Pat. No. 4,121,859, DeMey describes a metal-to-metal
seal using a gasket of resilient material that is compressed by
clamps. The gasket material forms a leak-proof seal and precludes
voids at the sealing interface. In U.S. Pat. No. 5,131,695, Wiser
describes an improved connection for joining two conduits with a
compressed variable washer formed from polytetrafluoroethylene
(Teflon) and some percentage of glass fiber. A stop shoulder
prevents over-tightening of the washer. The connection is primarily
for refrigeration systems and is reusable. While these schemes do
yield leak-proof seals, they are generally for connecting metallic
members to metallic members and for connecting members of like
materials to each other.
[0004] In U.S. Pat. No. 4,955,522, Stuhler presents a process for
the leak-proof joining of ceramic sealing discs to metallic
attachments. The ceramic sealing surface may be active soldered or
metallized then soldered to the metallic attachment. This method
can form a leak-proof seal between dissimilar materials, but the
seal cannot practically be re-used because the soldered seal is
effectively a permanent seal. Similarly, quartz or glass can be
permanently welded to a metallic attachment, but such a connection
is again not readily reusable or readily changeable and can be
expensive.
[0005] A gas-tight seal that can be used in elevated temperatures
and thermal cycles to join tubes of dissimilar materials is
described by Rynders et al. in U.S. Pat. No. 6,302,402. The
described seal is particularly for sealing a metallic tube to a
ceramic tube. The seal of Rynders et al. can work only when the
entire seal assembly is in a pressurized chamber in which the
chamber pressure is greater than the pressure within the tubes
being joined. The seal is impractical and inflexible for many
applications at least because of its need to be within a chamber
having pressure that is greater than the pressure within the tubes
being joined.
[0006] For quartz to metal connections, a single O-ring in a metal
housing is frequently used in a conventional manner. However, it is
difficult to consistently reproduce reliably gas-tight and
leak-proof seals using a single O-ring in a conventional manner.
Disproportionate forces and variations in surface features at the
sealing interface can produce voids and preclude a complete
seal.
[0007] A taper seal, such as at the end of a quartz tube and
opening of a complementary metal member can produce good seals, but
can be expensive due to the required tolerances in machining both
members to be joined. Integration of O-rings into the taper seal
does improve the sealing, but reproducible and complete sealing is
still difficult to achieve on a consistent basis.
SUMMARY OF THE INVENTION
[0008] What is needed is an improved sealing scheme and associated
methods. For example, what is needed are solutions that can
overcome at least some of the deficiencies of conventional seals,
for example, some of the deficiencies mentioned above.
[0009] According to an embodiment of the present invention, there
is an apparatus for combining with at least a seal to seal a
member. When the member is to be sealed, the member is at least
partially in a first space and at least partially encloses at least
a portion of a second space, the member including an opening to the
second space. The apparatus comprises a housing configured to
define, at least partially, a third space. The housing is
configured to facilitate maintaining pressure level in the third
space other than merely by exposing the third space to the first
space or to the second space. A pressure difference between the
third space and at least one of the first space or the second space
creates a force on the seal that promotes tightness of sealing
provided by the seal.
[0010] According to another embodiment of the present invention,
there is a method for tight sealing between a first space and a
second space, the second space being at least partially enclosed by
a member. The method comprises creating a pressure difference
between a pressure in a third space at a seal assembly and pressure
in each of the first space and the second space; and pushing,
caused by the pressure difference, against a seal in the seal
assembly to tighten sealing provided by the seal.
[0011] According to another embodiment of the present invention,
there is an apparatus for monitoring seal quality. The apparatus
includes a housing, a sensor, and an indicator. The housing is
configured to contain, at least partially, a space, pressure level
within the space being indicative of reliability or quality of
sealing in a seal. The sensor is one that is responsive to the
pressure level or a change in the pressure level. The indicator is
configured to convey information indicative of reliability or
quality of sealing in the seal.
[0012] According to one embodiment of the present invention, there
is a method for monitoring seal quality. The method includes
maintaining a pressure level in a space, the pressure level being
indicative of the reliability or quality of sealing in a seal;
monitoring the pressure level; and providing an indicator based on
the monitoring of the pressure level.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] In order to more extensively describe some embodiment(s) of
the present invention, reference is made to the accompanying
drawings. These drawings are not to be considered limitations in
the scope of the invention, but are merely illustrative.
[0014] FIG. 1 is a schematic section view showing an end of a first
tube and an end of a fitting or second tube that is to be sealed to
the first tube.
[0015] FIG. 2 is a schematic concept view showing an end of a first
member and an end of a fitting or second member being sealed to the
first member according to an embodiment of the present
invention.
[0016] FIGS. 3A and 3B are schematic section views showing
different stages of sealing, according to an embodiment of the
present invention.
[0017] FIG. 4 is a schematic concept view showing a coupler,
according to an embodiment of the present invention, and a first
and a second member, wherein the coupler facilitates sealing the
first member to the second member.
[0018] FIG. 5A is a schematic exterior view showing an embodiment
of the coupler of FIG. 4, in one example operating environment.
[0019] FIG. 5B is a schematic section view showing the coupler of
FIG. 5A.
[0020] FIG. 5C is a schematic section view, perpendicular to the
view of FIG. 5B, showing the coupler of FIGS. 5A and 5B.
[0021] FIG. 6A is a schematic flowchart indicating a sealing method
according to an embodiment of the present invention.
[0022] FIG. 6B is a schematic flowchart indicating a seal-quality
monitoring method according to an embodiment of the present
invention.
[0023] FIGS. 7A-7F are schematic section views each showing the end
of a first member and the end of a fitting or second member to be
sealed to the first member according to various embodiments of the
present invention.
DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS
[0024] The description above and below and the drawings of the
present document refer to examples of currently preferred
embodiment(s) of the present invention and also describe some
exemplary optional features and/or alternative embodiments. It will
be understood that the embodiments referred to are for the purpose
of illustration and are not intended to limit the invention
specifically to those embodiments. On the contrary, the invention
is intended to cover alternatives, variations, modifications and
equivalents and anything that is included within the spirit and
scope of the invention.
[0025] What is needed is a reusable and highly leak-resistant
(e.g., leak-proof) seal assembly, and associated methods.
Especially needed is for the seal assembly to be economical and
suited for use in sealing a junction between dissimilar materials
such as quartz and metal or glass and metal. Preferably, the seal
assembly is able to withstand elevated temperatures, multiple
thermal cycles, and/or operate in various environments. It is also
desired that the seal assembly has, or is able to accommodate, a
readily noticeable indicator of the status of the seal. Various
embodiments of the present invention help satisfy various subsets
of these needs.
[0026] FIG. 1 is a schematic section view showing an end 10 of a
first tube 12 and an end 14 of a fitting 16 or second tube 16 that
may be sought to be sealed to the first tube 12. No particular
sealing mechanism is shown in FIG. 1.
[0027] FIG. 2 is a schematic concept view showing sealing,
according to some embodiments of the present invention, between a
first member 12a and a fitting 16a or second member 16a. The first
member is at least partially in a first space 18. The fitting 16a
or second member 16a at least partially encloses a second space 20.
An arrow 22 schematically indicates that pressure is added to or
removed from some location at a portion 24 of the fitting 16a or
second member 16a to tighten a sealing 26 against the first member
12a. A pressure level is maintained, at the location, that differs
from pressure level in the first space 18 and/or pressure level in
the second space 20. The difference in pressure exerts a force on a
seal to tighten the sealing 26, for example, to make the sealing 26
leak-proof.
[0028] FIGS. 3A and 3B are schematic section views showing
different stages of sealing, according to an embodiment of the
present invention. FIG. 3A shows an end of a first member 12b, and
a structure 28 that is part of a fitting 16b or a second member
16b. The first member 12b is at least partially in an environmental
space 18a. The fitting 16a or second member 16a at least partially
encloses an internal space 20a In the simple configuration shown in
FIG. 3A, the first member 12b is simply a tube, and the structure
28 surrounds a segment of the first member 12b. The structure 28
helps to define a seal space 30. A plug or valve 32 (shown
schematically) also helps to define or partially close off the seal
space 30. A first seal 34 and a second seal 36 also each surround a
segment of the first member. The seals 34 and 36 may be, for
example, O-rings.
[0029] In the state shown in FIG. 3A, the first seal 34 does not
(yet) tightly seal the seal space 30 from the environmental space
18a. Similarly, the second seal 36 does not (yet) tightly seal the
seal space 30 from the internal space 20a. As shown, the seals 34
and 36 do not (yet) together tightly seal the internal space 20a
from the environmental space 18a.
[0030] FIG. 3B is a schematic section view showing the elements
from FIG. 3A under tight sealing, and undergoing tightening
sealing, according to the embodiment of FIGS. 3A and 3B of the
present invention. A nozzle 38 has been coupled, e.g., at least
temporarily, to the structure 28. The nozzle 38 has provided, and
is providing, suction to the seal space 30, as indicated by an
arrow 40. The suction may be being provided via the nozzle 38 by a
pump or reservoir. The suction in the seal space 30 "pulls" on the
seals 34 and 36 and moves them into contact and/or into tighter
contact with the structure 28 and with the first member 12b. For
example, the structure may have a feature(s) 42 that leaves a
gap(s) against the member 12b, and the gap(s) are plugged by the
seal when the seal is "pulled" by the suction toward the gap(s).
The feature(s) 42 may be, for example, protrusions or lips or the
like or any other competent feature. (Of course, "pulling" by
suction is merely a convenient way of referring to the pushing by a
pressure that is made dominant by the suction.) Preferably, the
valve 32 of FIG. 3A can be closed to maintain the tightened seal
even after the nozzle 38 (and the pump or reservoir) has been
decoupled from the structure 28.
[0031] The arrangement shown for demonstration in FIGS. 3A and 3B
is an example of one in which pressure in the seal space 30 is
capable of being maintained that differs from both pressure in the
environmental space 18a and pressure in the internal space 20a The
seal space is defined, at least in part, by an external wall of the
member and an internal wall of the structure 28. The arrangement is
especially beneficial when the first member 12b is made of a
different material as another member that is to be coupled to the
first member. The other member is, e.g., the second member 16b
itself or a non-shown member that is coupled (not shown) to the
fitting 16b. For example, the non-shown member may be of metal and
may be connected to a metal fitting 16b using any metal-to-metal
connection. For example, the first member 12b may be made of
quartz, glass, ceramic, plastic, or the like, or any other
non-metal material, or a combination thereof. For example, the
first member 12b may be a quartz tube. The fitting 16b or second
member 16b may couple to, or include a stopper, plug, end piece, or
blank, so as to close and seal the opening of the first member
12b.
[0032] FIG. 4 is a schematic concept view showing a coupler 44,
according to an embodiment of the present invention, and a first
member 12c and a second member 16c. The coupler 44 facilitates
sealing the first member 12c to the second member 16c. In
operation, the coupler 44 is sealed to the first member 12c and is
sealed to the second member 16c, and the first member 12c is so
coupled to the member 16c.
[0033] FIG. 5A is a schematic exterior view showing a particular
embodiment 46 of the coupler 44 of FIG. 4, in one example operating
environment. The coupler 46 is also a particular embodiment of the
sealing assembly shown in FIGS. 3A and 3B. A first member 12d is to
be coupled to a second member 16d. In the example operating
environment of FIG. 5A, the first member 12d may be, for example, a
quartz tube coupled to a furnace 48.
[0034] FIG. 5B is a schematic section view showing the coupler of
FIG. 5A. The section is along a radial plane relative to a
longitudinal axis of the first member 12d, as indicated in FIG. 5A.
FIG. 5C is a schematic section view, perpendicular to the view of
FIG. 5B, as indicated by a section line in FIG. 5B. FIG. 5C shows
the coupler of FIGS. 5A and 5B.
[0035] As shown in FIG. 5C, there is an environmental space 18b,
the first member 12d partially encloses an internal space 20b, and
a structure 52 partially defines and encloses a seal space 30a.
Operation of the coupler 46 is as has been discussed in connection
with FIGS. 3A and 3B, and is understood by comparing FIG. 5C to
FIG. 3B.
[0036] Preferably, there is a first end piece 50 and a second end
piece 54 that each help keep the seals 34a and 36a in sufficient
proximity to the seal space 30a for the anticipated level of
evacuation of the seal space 30a to "pull" the seals 34a and 36a
into tight sealing position. Thus, the end pieces 50 and 54 can
free a human technician setting up the coupler 46 from having to
manually position the seals 34a and 36a next to the structure 52.
Further the end pieces 50 and 54 can prevent the seals 34a and 36a
from being blown too far away for re-tightening when the seals 34a
and 36a are sought to be loosened by a burst of gas or fluid into
the seal space 30a. The end pieces 50 and 54 may be separate pieces
from the structure 52, or they may be removably or permanently
connected to the structure 52 by any mechanism whatsoever, for
example, threading, friction, bonding, welding, spring force, or
the like, or any other competent mechanism. In FIG. 5C, the end
pieces 50 and 54 are both threaded onto matching threads in the
structure 52. Note that, in general, the annular "groove" in which
the seals 34a and 36a are situated can be allowed to be large
enough such that the seals 34a and 36a can shift around slightly,
as long as the suction is strong enough to pull and hold the seals
34a and 36a tightly to the sealing surfaces against which the seals
34a and 36a are to seal. However, in the embodiment shown in FIG.
5C, the end pieces 50 and 54 can be threaded far enough into the
structure 52 that the "groove" constrains the seals 34a and 36a,
even before suction is applied, such that the end pieces 50 and 54
cause the seals 34a and 36a to already touch the surfaces against
which they are to make a seal, even before suction is applied.
[0037] According to one embodiment of the coupler as particularly
shown in FIGS. 5A and 5B, there a seal assembly that includes two
O-rings, a first, second, and third piece having central channels
in whole or in part. Two members are to be joined by the coupler.
The coupler is configured to be moved, selectively positioned and
connected to the members being joined. One O-ring is positioned
between the first and second piece of the seal assembly. The seal
assembly may refer to either the combined pieces of the seal
housing or the entire seal element, including, e.g., the O-rings.
The second O-ring is positioned between the second and third piece
of the seal assembly, and there exists a volume contained by the
two O-rings, the attached member, and the second piece. There is an
opening to this small volume in the second piece through which
means can be applied to evacuate the volume to low pressure or
vacuum. The low pressure or vacuum places an inward force on the
two O-rings, which causes them to form a leak proof seal with the
second piece and attached member. In this way, the seal is actuated
by pressure differential and a closing device or shut-off valve at
or connected to the opening on the second piece is used to hold the
pressure differential and maintain the leak-proof seal. The valve
can be any type of competent valve, for example, a valve that
automatically closes upon withdrawal of the suction or pressure
nozzle from the seal assembly. Generally, the valve may be a check
valve, a manual valve, or any other competent valve, whether it
uses spring-loading, balls, disks, or whatever other competent
mechanisms. Valves are well known.
[0038] The O-rings can be plastic, rubber, silicone, Teflon,
nitrile, Viton, fluorosilicone, neoprene, Kalrez, polyurethane,
vulcanized, metal, or the like, or any other competent material, or
a combination of materials. The members to be joined can be of like
or dissimilar materials, including metal, quartz, glass, ceramic,
plastic, or other material. The members can be cylindrical,
tubular, ellipsoidal or other shape, and one of the members can be
a plug, stopper, end-piece, or blank. One or all of the members may
be able to hold fluid or gas, either statically or flowing. The
leak-proof seal may be opened or unsealed by opening the small
volume contained by the O-rings, attached member, and second piece
to atmosphere or gases such as compressed air, nitrogen, argon,
helium, hydrogen, or other gas. The small volume may also be
pressurized to higher than environmental pressure, e.g., higher
than atmospheric pressure, to open the seal. This higher pressure
may be restricted to be below a certain amount, e.g., below 200
pounds per square inch. The pressurization removes the inward
forces on the O-rings and allows the members to be more easily
separated. The seal is reusable and through selection of materials
for the seal assembly and O-rings, can operate in elevated
temperatures, multiple thermal cycles, toxic gas or material
environments, flammable gas environments, and in various pressure
environments. Either or both O-rings can be intentionally
configured, e.g., sized, such that if they are not being tightened
by suction, then they will not provide leak-proof sealing.
[0039] The coupler can include a sensor and an indicator of the
status of the seal. The indication can reveal that the seal is in
operation and leak-proof or that it is opened and unsealed. The
indicator can be visual, such as by LED, a flashing light source,
an analogue or digital gauge, an extending or retracting button, or
a color change, or the like or any other competent mechanism. The
indicator can also be audio, e.g., a buzzer or bell or voice
announcement or alarm, or the like or any other competent
mechanism, or a combination of visual and audio or any other
sensory input. The sensor can be a sensor of the pressure level in
the seal space. The indicator can be a continuous indicator and/or
an alarm that is raised, or is made especially apparent, in case of
seal failure. The sensor can also include a wired or wireless
transmitter that sends signals to a monitoring computer or pager or
telephone, or the like.
[0040] A push-rod, slide, or other device can be used to open the
O-ring seal. This may be used when the seal does not easily unseal
after the volume contained by the two O-rings, the attached member,
and the second piece is opened to atmospheric pressure or higher
pressure. A mechanical force is imparted on the O-rings, attached
member, or seal assembly to break the leak-proof seal.
[0041] According to another embodiment, the seal assembly is
configured so that the small volume contained by the O-rings, the
attached member, and the second piece is pressurized to place an
outward force on the O-rings. The O-rings are forced against the
seal assembly (housing) and the attached member to form the
leak-proof seal. The seal is actuated by the differential pressure
between the higher pressure in the small contained volume and the
outside pressure.
[0042] In some embodiments of the invention, the seal housing is be
configured so that only one O-ring or other type of seal is needed,
where the O-ring is tightly fit between two pieces of the housing
with the small open volume above it. This small volume is
pressurized and the O-ring is forced against the attached member to
form the leak-proof seal.
[0043] According to a specific embodiment of the invention, a
leak-proof seal assembly is used for connecting quartz, glass,
ceramic, or plastic to metal and is used for the production of
materials and nanostructures. The nanostructures include nanowires,
nanotubes, carbon nanotubes, nanoparticles, or thin films of
materials where at least one of the dimensions of the structures is
less than 100 nanometers. The nanostructures may be produced by
chemical vapor deposition, laser vaporization, and other known
method. These techniques can utilize the leak-proof seals to add
control, eliminate contamination and safety problems, and achieve
more reproducible results. More specifically, for the synthesis of
carbon nanotubes, the leak-proof seal precludes oxygen or air leaks
at the sealing interfiices. This is a very important concern for
quality synthesis of the carbon nanotubes at high temperatures,
where oxygen can damage or destroy the carbon nanotubes and hinder
or completely prevent synthesis.
[0044] Generally, seal assemblies according to embodiments of the
present invention may be large or small, as appropriate to the
member(s) being sealed. According to a specific embodiment, the
leak-proof seal assembly is used for connecting tubing or other
members having an outside diameter that is no less than 1/8 of an
inch. For example, the central channel of a coupler according to
the embodiment is no less than 1/8 of an inch. Couplers can also be
restricted to couple members having a diameter that is less than,
for example, 16 inches.
[0045] According to an embodiment of the invention, a reusable
leak-proof seal apparatus for connecting multiple members is
provided that includes two O-rings and a seal assembly housing. The
volume is contained between the two O-rings, one of the members,
and the seal assembly housing. This volume is evacuated to low
pressure or to vacuum, which results in an inward force on the
O-rings and forms a leak-proof and gas-tight seal. The present
invention is especially suited for quartz or glass to metal
connections, such as in some heated furnace equipment setups. The
seal assembly may include an indicator of the nature of the seal,
particularly whether it is closed and fluid-tight or open and
unsealed. In an alternative embodiment, the volume is pressurized
and an outward force on the O-rings brings about the differential
pressure actuated seal.
[0046] FIG. 6A is a schematic flowchart indicating a sealing method
70 according to an embodiment of the present invention. In a step
72, a seal assembly is coupled to a member. For example, the seal
assembly may be an embodiment of the present invention as is
discussed in the present document. In a step 74, a pressure
difference is created at the seal assembly to tighten sealing of
the member. In a step 76, the pressure difference is electively
reduced or eliminated or reversed to cease tightening of the
member.
[0047] FIG. 6B is a schematic flowchart indicating a method 80 for
monitoring seal quality according to an embodiment of the present
invention. In a step 82, a pressure level is established in a
space. The pressure level is indicative of the reliability or
quality of sealing in a seal. For example, the pressure level may
be the pressure level in the seal space discussed in connection
with FIGS. 3A, 3B, 5A and 5B. In a step 84, the pressure level is
monitored. In a step 86, an indicator is provided based on the
monitoring of the pressure level from the step 84.
[0048] FIGS. 7A-7F are schematic section views each showing the end
of a first member and the end of a fitting or second member to be
sealed to the first member according to various embodiments of the
present invention.
[0049] In FIG. 7A, an embodiment of the seal assembly of FIGS. 3A
and 3B is shown in which seals 34b and 36b are not O-rings but are
seals having a concave surface, such as taught in U.S. Pat. No.
6,302,402, to Rynders et al., which is hereby incorporated by
reference. Pressure applied to the concave surface tends to flex
the seals in a manner tending to reduce the concavity of the
surface. This flex tightens the seals.
[0050] In FIG. 7B, a seal assembly creates a pressure difference by
applying high pressure, and not suction, to a seal space. The high
pressure pushes two seals 34c, shown as O-rings, tighter against
gaps between the seal housing and the member being sealed.
[0051] In FIG. 7C, a seal assembly also creates a pressure
difference by applying high pressure, and not suction, to a seal
space. FIG. 7C shows that, instead of two separate seals, such as
two O-rings, a single seal (or two mutually linked seals) may be
used. The single seal shown is one that has a bowed cross section.
The pressure difference tends to unbow the seal, to thereby tighten
both the sealing between the environmental space and the seal space
and also the sealing between the internal space and the seal space.
FIG. 7D shows another embodiment of the seal assembly discussed in
connection with FIG. 7C. The seal assembly of FIG. 7D is shown as
using a seal such as the seals taught in the incorporated U.S. Pat.
No. 6,302,402, to Rynders et al.
[0052] In FIG. 7E, a seal assembly receives pressure into its seal
space not directly via an external opening in the seal-space
housing 16e. Instead, the seal assembly receives its pressure via a
channel 62 that is defined by a member 12e that is being sealed.
Similarly, for suction-based seal assemblies according to the
present invention, the pressure received can be negative pressure,
or suction, and thus the seal space can be evacuated from such a
channel.
[0053] Actually, in FIG. 7E, the shown portion of member 12e can be
thought of as a portion of an embodiment of a coupler 44 of FIG. 4,
and seal-space housing 16e can be thought of as a member that is
being sealed that has had an internal groove scored into its
interior wall, near its opening edge. More generally, in the
drawings of the present document, the features of the seal housing
or second member may instead be considered to be features of the
first member, and vice versa.
[0054] In FIG. 7F, a seal assembly is shown that creates a seal
against an internal wall of a member 12f that is being sealed. The
seal assembly shown is a suction-based embodiment using O-rings,
but of course other embodiments may also similarly be configured to
use the interior of the member 12f for sealing. For example, the
seal assembly is a through coupler, but an end-cap embodiment can
also be used that is closed at the bottom of FIG. 7F.
[0055] Throughout the description and drawings, example embodiments
are given with reference to specific configurations. It will be
appreciated by those of ordinary skill in the art that the present
invention can be embodied in other specific forms. The scope of the
present invention, for the purpose of the present patent document,
is not limited merely to the specific example embodiments of the
foregoing description, but rather is indicated by the appended
claims. All changes that come within the meaning and range of
equivalents within the claims are to be considered as being
embraced within the spirit and scope of the claims.
* * * * *